Merge from Chromium at DEPS revision 222756

This commit was generated by merge_to_master.py.

Change-Id: I085d892f6f1583a45f10eb394f195bbea5a334ef
diff --git a/Source/core/css/CSSMediaRule.idl b/Source/core/css/CSSMediaRule.idl
index 71185a7..0f1d76d 100644
--- a/Source/core/css/CSSMediaRule.idl
+++ b/Source/core/css/CSSMediaRule.idl
@@ -23,8 +23,7 @@
     readonly attribute MediaList media;
     readonly attribute CSSRuleList cssRules;
 
-     [RaisesException] unsigned long      insertRule([Default=Undefined] optional DOMString rule,
-                                                 [Default=Undefined] optional unsigned long index);
-    [RaisesException] void               deleteRule([Default=Undefined] optional unsigned long index);
+    [RaisesException] unsigned long insertRule(DOMString rule, unsigned long index);
+    [RaisesException] void deleteRule(unsigned long index);
 };